Best known for excitedly profiling the mega-rich on 1980s-era television (“Champagne wishes and caviar dreams!”), Mr. Leach on this recent Saturday afternoon was wearing a beat-up blue baseball cap, and his much-parodied British accent was a bit muted. Getting down to the business of lunch, a napkin tucked into the V-neck of his sweater, he wearily wrestled with a Vegas-size glop of Gruyère floating atop a vat of French onion soup.